github: add issue template

Signed-off-by: Tianling Shen <cnsztl@immortalwrt.org>

.github/ISSUE_TEMPLATE/bug-report.yml

@@ -0,0 +1,82 @@
+name: Bug report
+description: Create a bug report to help us improve
+labels:
+  - bug
+body:
+  - type: textarea
+    id: description
+    attributes:
+      label: Describe the bug
+      description: A clear and concise description of the bug.
+    validations:
+      required: true
+  - type: input
+    id: version
+    attributes:
+      label: ImmortalWrt version
+      description: |
+        The ImmortalWrt release or commit hash where this bug occurs (use command below).
+        ```. /etc/openwrt_release && echo $DISTRIB_REVISION```
+    validations:
+      required: true
+  - type: input
+    id: target
+    attributes:
+      label: ImmortalWrt target/subtarget
+      description: |
+        The ImmortalWrt target and subtarget where this bug is observed (use command below).
+        ```. /etc/openwrt_release && echo $DISTRIB_TARGET```
+    validations:
+      required: true
+  - type: input
+    id: device
+    attributes:
+      label: Device
+      description: The device exhibiting this bug.
+    validations:
+      required: true
+  - type: dropdown
+    id: image_kind
+    attributes:
+      label: Image kind
+      options:
+        - Official downloaded image
+        - Self-built image
+    validations:
+      required: true
+  - type: textarea
+    id: reproduce
+    attributes:
+      label: Steps to reproduce
+      description: Steps to reproduce the reported behaviour.
+  - type: textarea
+    id: behaviour
+    attributes:
+      label: Actual behaviour
+      description: A clear and concise description of what actually happens.
+  - type: textarea
+    id: expected
+    attributes:
+      label: Expected behaviour
+      description: A clear and concise description of what you expected to happen.
+  - type: textarea
+    id: additional
+    attributes:
+      label: Additional info
+      description: Add any additional info you think might be helfpul.
+  - type: textarea
+    id: diffconfig
+    attributes:
+      label: Diffconfig
+      description: |
+        In case of a self-built image, please attach diffconfig.
+        ```./scripts/diffconfig.sh```
+      render: text
+  - type: checkboxes
+    id: terms
+    attributes:
+      label: Terms
+      description: By submitting this issue, you agree to the terms below.
+      options:
+        - label: I am reporting an issue for ImmortalWrt, not an unsupported fork.
+          required: true

.github/ISSUE_TEMPLATE/config.yml

@@ -0,0 +1,9 @@
+---
+blank_issues_enabled: true
+contact_links:
+  - name: ImmortalWrt community
+    url: https://t.me/ctcgfw_openwrt_discuss
+    about: Consider reaching out to our community to get help. ImmortalWrt is a complex software project with many pitfalls; there is a good chance someone can help you solve your issue in no time.
+  - name: OpenWrt documentation
+    url: https://openwrt.org/docs/start
+    about: The OpenWrt documentation contains a lot of valuable information.